In many vehicles in use at the present time, the driver and front seat passenger are provided with a three-point seat-belt and, in many cases, are additionally provided with at least one air-bag to restrain the passenger in the event that a front impact should occur. The restraining effect of the three-point seat-belt, or the restraining effect of the combination of the three-point seat-belt and the air-bag, is such that in a typical accident situation the occupant is subjected to an appropriate restraining force, which is not too large and which is not too small, so that the vehicle occupant can be decelerated in an optimum manner.
It has been found, however, that in a far-side side impact situation, that is to say a situation in which there is a side impact on the side of the vehicle which is remote from the occupant, and also in a roll-over situation, there is a risk that the occupant will slip out of the shoulder part of the three-point belt. Of course, if the occupant does slip out of the seat-belt in this way, the seat-belt cannot provide optimal protection.
To avoid this problem arising, and also to provide a better distribution of the load applied to the torso of the occupant by the seat-belt arrangement, it has been proposed to combine a two-point belt with the known three-point belt. The two-point belt is a diagonal belt which forms a “mirror image” of the diagonal part of the three-point seat-belt. Thus the two-point belt extends over the other shoulder, and diagonally across the torso.
At this time, however, the typical combination of a three-point belt and a two-point belt is such that use of the two-point belt is optional, and the occupant may or may not use the two-point belt. If the occupant does use the two-point belt in addition to the three-point belt, the risk of injury in a far-side side impact or roll-over situation is reduced.
However, if a seat occupant uses the two-point belt in addition to the three-point belt, the total restraining force applied to the occupant in an accident situation is increased and consequently the restraining force applied to the seat occupant may be too large, causing the seat occupant to decelerate in an undesirable manner.
The present invention seeks to provide an improved safety arrangement.